Coast Guard, local, state and federal emergency officials took a Coast Guard helicopter flight Friday morning, July 4, 2014, to survey Hurricane Arthur's impact on North Carolina's Outer Banks. This photo of an unspecified NC location was uploaded to the Coast Guard Mid-Atlantic's Facebook page on Friday. Courtesy of the U.S. Coast Guard

Coast Guard, local, state and federal emergency officials took a Coast Guard helicopter flight Friday morning, July 4, 2014, to survey Hurricane Arthur's impact on North Carolina's Outer Banks. This photo of an unspecified NC location was uploaded to the Coast Guard Mid-Atlantic's Facebook page on Friday. Courtesy of the U.S. Coast Guard

Climate report warns of 4-foot floods on NC coast

Citing the rising sea level, a national climate-policy group warned Tuesday that the North Carolina coast could see floods as much as 4 feet above the high tide line during the next 30 to 60 years, jeopardizing 61,000 homes along the coast.

Climate Central, a New Jersey-based nonprofit, published interactive maps (online at bit.ly/1zFPAHL) that it said could help residents of North Carolina coastal towns gauge the risk of flooding, which is expected to increase in coming years as the seas rise. In a 30-page report, the group cited what it called medium-range projections for a sea-level rise on the North Carolina coast of 1.1 feet by 2050 and 3.8 feet by 2100.

A 4-foot flood would submerge an estimated 2,045 square miles of land, mostly in Hyde, Dare and Tyrrell counties – including real estate worth $8.8 billion, mostly in New Hanover and Brunswick counties, the Climate Central report said.

The report came as a panel of North Carolina coastal engineers and geologists was preparing to start work on a new sea-level forecast for the state.

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The N.C. Coastal Resources Commission’s science panel alarmed beach developers and Republican legislators with its warning in 2010 of a possible 39-inch rise in sea level by the end of this century. The legislature responded with a moratorium on state regulations and plans based on sea-level rise, and it set guidelines for developing a new official state forecast to be formally released in 2016.

The prediction for 39 inches by 2100 was consistent with warnings from science groups around the world – but disputed by coastal developers and climate-science skeptics – that hotter temperatures will cause the rise in sea levels to accelerate in the latter half of the century.

But only a little acceleration is expected over the next three decades, and the new forecast is widely expected to come in at somewhere around 8 inches for the next 30 years.

The science panel will be asked to provide separate forecasts for different parts of the coast, and coastal dwellers will be watching to see how much those numbers vary from north to south.

The historical record shows a substantial difference from one end of the North Carolina shore to the other according to Spencer Rogers, a coastal erosion specialist for N.C. Sea Grant, and a science panel member.

The tidal gage at Duck indicates that the sea there has risen about 15 inches in the past 90 years, Rogers said, partly because the northern end of the Outer Banks is part of a land mass that has been sinking slowly during recent centuries.

At Wilmington, the estimated sea-level rise for the past 90 years is just 7 inches.